Tobacco treatment



Patented July 7, i953 'ToBAcoo TREATMENT Walter G. Frankenburg,Millersville, Pa., assignor to General Cigar (10., Inc., New York, N.Y., a corporation of New York g No Drawing. Application November-1,1947,Y I Serial No. 783,626

, 10 Claims.

, This invention relates to the treatment of tobacco and, moreparticularly, to the fermentation of tobacco toirender the tobaccotender and pleasant-smelling and to developisuch smoking qualities asaroma and mellowness.

In general, tobacco which has been harvested is cured (dried) by hangingthe leaves in a suitably ventilated barn. During the curing period whichis usually about 4 months, the tobacco mentation.

commercial application.

bacco.

procedures.

which follows.

numbers 25 to '28, (Mn, Fe, Co and Ni), in-

elusive. It is advisable to select compounds ofstable under theconditions of fermentation. Manganese and iron catalysts are preferred.Catalysts comprising two metals either as physical mixtures of two metalcompounds or as single complex compounds containing the desired metalsare often used to advantage. Such salts of the-catalytic metals as thenitrates, sillfates, acetates, citrates and tartrates represent suitablecatalysts for the process of my inven- The catalyst is usually appliedto the tobacco before fermentation in the form of an aqueous solutioneither by spraying the solution or by dipping the tobacco in thesolution. The addition of water to cured and sweated tobaccopreparatoryto fermentation or resweating is a conventional operation. In essence,therefore, my invention involves the selection of chem-=, icalsubstances which promote or catalyze the fermentation of tobacco and theaddition of these selected substances to tobacco undergoing fer- Theproportion of catalyst added to the tobacco will varywith the nature ofthe particular tobacco that is being treated and the selected catalystand the results which are to be achieved In general, the proportion ofcatalyst is less than 0.5% by weight of the dry tobacco, and preferablyis in the range of about 0.005% to 0.1%, the foregoing percentages beingbased on the molecular weight of the catalytic element or metal in thecatalyst compound. As a rule, tough tobaccos, i. e., those failing torespond satisfactorily to fermentation without added catalysts, andtobaccos having unusually high contents of nicotine show more markedlythe benefits of my catalytic fermentation process, which include, insome instances,

In the preparation of cigarette tobacco, "a slower and less vigorousform of fermentation known as aging is practiced. My fermentation For instance, an aqueous solution of the catalyst is sprayed on the tobacco,say in an amount not exceeding 5%--byweight of the dry tobacco. Thusyaconcentration of catalytic metal, e. g., manganese and/or iron,corresponding to about from 0.01% to 0.05% by weight of the dry tobaccois introduced and the tobacco is then subjected to the usual agingprocess.

undergoes certain chemical changes and turns brown. Thereafter, thetobacco leaves are graded according to size and quality and the variousgrades are packed incases to undergo natural tion. sweating. Tobaccoisfrequently sweated for a period of 2 to 3 years during which timeadditional chemical changes occur in the tobacco leaves. The next stepin the preparation of tobacco for smoking purposesis fermentation orresweating; fermented tobacco is frequently re 'ferred to as resweatedtobacco because the pre- V liminary or first sweating is a mild form offer- In spite of the extensive art bearing on the fermentation oftobacco, occasions arise when tobacco of a given harvest year orlocality or mentation. species fails to respond satisfactorily to theknown methods of, fermentation and, accordingly, cannot be utilized inthe production of cigars, cigarettes and 'othersmoking products. It isclear that these vagaries of certain lots of by the fermentation.tobacco lead to considerable economic losses for which, to my knowledge,no remedy has been previously suggested, much less developed for Theprincipal object of this invention is to pro- 35, vide an improvedprocess for fermenting to= Another important object is to providea'process for fermenting tobacco which does not satisfactorily respondto conventional fermenting 40 A further object is to develop superiorsmo'ka c lerati n of fermentation. ing qualities in tobacco,particularly tobacco of low grade, by fermenting the tobacco in thepresence of promoters or catalysts. p

Additional objects andadvantages of my catalysts are' advantageouslyused in the convention will be evident from the description v t m agingcigarette t I have discovered that thereare chemical substanceswhichwhen added to tobacco which is ,50 to be fermented act as promoters orcatalysts in the fermentation process.- The catalysts of my inventionare compounds of elements of Series 4 of the Mendeleeff Periodic Tablehaving atomic sweat.

Further refinements of the process which I have developed includepressure changes and wetting agents. By subjecting tobacco to a reducedpressure, say below 50 mm. Hg absolute, and immersing the thusvacuumized tobacco in an aqueous catalyst solution, the liquidinfiltrates more thoroughly and quickly into the tobacco because theplant cells are at least partially evacuated of gas which tends toobstruct the penetration of liquid. Wetting agents add" ed to theaqueous catalyst solution also function to drive the liquid into thetobacco and thus aid in the fermentation process. Less than 0.05% byweight of wetting agents like sulfonated alcohols or sulfonated alkylbenzenes dissolved in the aqueous catalyst solution materially improvesthe penetration of the liquid into the tobacco.

For a more detailed description and further clarification of myinvention, specific examples will now be presented.

Eaz'cmpie 1 Pennsylvania broadleaf tobacco grown in abnormally dryseasonwasharvested, cured and subjected to a three-year period of naturalAfter this initial processing, the tobacco was still very hard toferment. The tobacco consisting of leaves 22 inches in length was of anorange color and felt gummy and soft; all these signs indicated. itsrawness. The nicotine content was 5.2% by weight of the dry tobacco.Such a highnicotine content is characteristicoi tobacco which is veryresistant to fermentation.

.A 300-110. case of thistobacco was divided into twoequal test lots Aand B. ,Lot. A was immersed in water so that it took up an amount ofwater equal to 48% of the-dry tobaccoweight. Lot B was similarlyimmersed in an aqueous solution of fermentation catalyst. Thecomposition of the solution was:

Water gallons 90 Manganese sodium. citrate (Mn content about (manganesecitrate soluble N 'F. VII) "pounds" 2.2 Wetting agent (dioctyl ester ofsodium sulfo succinic acid); ounces 4.5

relative humidity and 112 F. After a days, the

cases were removed. from thisroom, opened, and the tobacco of each caseshaken and repacked. The cases were brought back into the heated 100111and remained. there 7 days (second heat). Another shaking then followed.The two cases were returned to the fermenting room for a third heat of12 days, a fourth heat of 21 days, a fifth heat of 4 /2 weeks, asixth'heat of 1 /2 months, and a seventh of 2 /2 months, eachheat-following a shaking and repacking operation.

After the fourth heat, the tobacco of lot B which had received thesolution containing manganese, showed 'a more pronounced loss of surfacegums, a slightly darker color, a more tender textureand a cleaner,less-pungent smell than the tobacco of lot .A which received only water.This difierence in favonof iotB containingxthefermentation catalystbecame more and moremarked with the continuation of the fermentationprocess. .Afterthe seventh heat,

strong in texture and unclean in smell.

nicotine content of 1.63%

the tobacco of lot 13 had lost all its moisture, was dark brown, verytender in texture and possessed a slightly ammoniacal aromatic odor,whereas the tobacco of lot A was still slightly moist, Even after anadditional heat, the tobacco of lot A was still inferior in feel,appearance and smell to that of .lot B. By chemical analysis, thefermented (seven heats) tobacco of the catalyst lot B had a by weight ofdry tobacco, while the fermented (eight heats) tobacco of the water lotA had a nicotine content of 2.32%. Smoking tests showed conclusivelythat .theitobacc'o .of lot B was superior to that of lot A..in burningcharacteristics, mildness and Example 2 Pennsylvania tobacco which wasgrown in a very dry season, cured'and stored for a period of naturalswea; of four years, showed all the exterior signs of abnormal 'rawnessor toughness. This tobacco, consisting of 18-inch leaves, was known toyield an end product of unsatisfactory smoking qualities, even iffermented under drastic conditions. 'Two lots C and'D of this tobaccowere used in comparative tests.

The'tobacco of lot C was immersed in an aqueous solution containing byweight 0.3% of manganese sodium citrate, 0.5% of iron ammonium citrate(iron content 17.5%) and 0.035% of wetting agent '(dioctyl ester ofsodiumsulfosuccinic acid). Ihe tobacco'took up an amount of catalystsolution corresponding to 51% of its Weight before immersion.Fermentation was conducted in a series of heats and shakings asdescribed in Example 1 except that the heat' periods were about 25%shorter. During the third heat, the tobacco showed a spontaneous rise ofits temperature, reaching a maximum temperature of 129 F. After thethird heat, the color of the tobacco changed to a very dark brown.Starting with the fifth heat, the tobacco texture began to becomeconsiderably more tender, and the smell started to change to the typicalammoniacal, aromatic odor characteristic of well fermented tobacco.After the sixth heat, the fermentation was stopped and the tobaccopossessed very acceptable smoking quali= ties. Thenicotine content haddecreased from 6.1% to.2.3%.

The tobacco of lot 1) was immersed in water containing only 0.0l% byweight of the wetting agent used in connection with lot C. The tobaccotook up an amount of water corresponding to 52% by weight of drytobacco. The tobacco did notrespond at alltoefiortsto startitsfermentation, although it was subjected to eight heats and shakings.The nicotine content only decreased from 5.5% to 4.9%, and the smokingqualities of 7 the tobacco were distinctly unacceptable.

Example '3 I tation; the quantity of manganese compound thus introducedinto the tobacco was about 0.06% by weight of the dry tobacco. Thecatalytically fermented tobacco was successfully employed as bindertobacco in making c s.

As indicated hereinbefore, good fermentation of tobaccois evaluated interms of the properties of the fermented tobacco. Thus, it is generallyobserved that satisfactory fermentation weakens the tobacco tissues sothat the tobacco becomes desirably tender, eliminates or materiallydecreases surface gums so that the gummy feel of tobacco is destroyed,develops a pleasant aromatic odor in the tobacco, reduces the alkaloid(especially nicotine) content of the tobacco, and renders the tobaccomilder in smoking tests. The value of the catalytic fermentation processof my invention is more readily appreciated when judged on the basis ofthe foregoing criteria.

While I have referred to compounds of manganese, iron, cobalt and nickelas promoters or catalysts for the fermentation of tobacco, the exactrole of these compounds which I add to tobacco is not clear to me.However, it is sufficient that desirable results are obtained whentobacco is fermented in accordance with the teachings of thisspecification.

The term, fermentation, has herein been used in the same general sensecommonly understood in the tobacco industry; that is to say, the termdoes not imply that any process simila to the process of alcoholicfermentation occurs in tobacco and does not mean that microorganisms arenecessarily involved. Furthermore, it is well known in the tobaccoindustry that the fermentation of tobacco commences at about roomtemperature. Thus, studies on the fermentation of tobacco were reportedin 1934 in the Journal of Agricultural Research (volume 49, No. 2, page145) showing that fairly evident thermogenesis (generation of heat),which is characteristic of tobacco fermentation, begins at about 16 C.(61 F.).

The foregoing description and examples are intended to be illustrativeonly. The many possible variations and modifications of my inventionconforming to its spirit are to be considered within the scope of theappended claims.

What I claim is:

1. In the fermentation of tobacco, the improvement which compriseswetting tobacco substantially uniformly with an aqueous solution of awater-soluble, fermentation catalyst compound of an element selectedfrom Series 4 of the Mendeleeff Periodic Table and having an atomicnumber between 25 and 28, inclusive, and subjecting the tobacco with thethus applied catalyst compound to fermentation in the temperature rangeof about 16 to 54 C.

2. The process of claim 1 wherein the selected element is manganese.

3. The process of claim 1 wherein the quantity of fermentation catalystcompound applied to the tobacco is in the range of about 0.005% to 0.1%by weight of the dry tobacco, said percentage being based on themolecular weight of the catalytic element in said fermentation catalystcompound.

4. The process of claim 1 wherein the tobacco is subjected to a pressuresubstantially below atmospheric pressure to vacuumize the same, and theaqueous solution of the fermentation catalyst compound is then appliedby immersing the vacuumized tobacco in said aqueous solution.

5. The process of claim 1 wherein the aqueous solution of thefermentation catalyst compound contains a wetting agent to facilitatepenetration of said aqueous solution into the tobacco.

6. The process of claim 5 wherein the watersoluble, fermentationcatalyst compound is manganese sodium citrate.

7. The process of claim 1 wherein the tobacco initially has a nicotinecontent exceeding about 5% by weight of the dry tobacco.

8. The process of claim 7 wherein the selected element is manganese.

9. The process of claim 7 wherein the aqueous solution of thefermentation catalyst compound contains a wetting agent to facilitatepenetration of said aqueous solution into the tobacco.

10. The process of claim 9 wherein the watersoluble, fermentationcatalyst compound is manganese sodium citrate.

WALTER G. FRANKENBURG.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Technical Mycology, La Far, Dgs. 45 to 48, inclusive, 1903,

Annual Review of Biochemistry, vol. V, 1936, pg. 28.

Journal of Biological Chemistry, vol. 155, Sep- I tember-October 1944,pp. 137 to 141, inclusive.

1. IN THE FERMENTATION OF TOBACCO, THE IMPROVEMENT WHICH COMPRISESWETTING TOBACCO SUBSTANTIALLY UNIFORMLY WITH AN AQUEOUS SOLUTION OF AWATER-SOLUBLE, FERMENTATION CATALYST COMPOUND OF AN ELEMENT SELECTEDFROM SERIES 4 OF THE MENDELEEFF PERIODIC TABLE AND HAVING AN ATOMICNUMBER BETWEEN 25 AND 28, INCLUSIVE, AND SUBJECTING THE TOBACCO WITH THETHUS APPLIED CATALYST COMPOUND TO FERMENTATION IN THE TEMPERATURE RANGEOF ABOUT 16* TO 54* C.